"She always leaves a little gift or something in [George and Princess Charlotte's] room when we go and stay [with her]. That just shows her love for her family," the Duchess of Cambridge said in the TV special, created in honor of Queen Elizabeth's 90th birthday in April 2016.

In Our Queen at Ninety, Kate — who married into the royal family when she tied the knot with Prince William back in April 2011 — additionally revealed the first-ever Christmas gift she gave the Queen. "I can remember being at Sandringham, for the first time, at Christmas. And I was worried what to give the Queen as her Christmas present," the mom-of-two said.

"I was thinking, 'Gosh, what should I give her?' I thought back to what would I give my own grandparents. And I thought, 'I'll make her something.' Which could have gone horribly wrong. But I decided to make my granny's recipe of chutney," Kate continued. "I was slightly worried about it, but I noticed the next day that it was on the table. I think such a simple gesture went such a long way for me and I've noticed since she's done that on lots of occasions and I think it just shows her thoughtfulness, really, and her care in looking after everybody."

Check out the gallery to see the cutest photos of Prince George and Princess Charlotte!

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Sept. 24, 2016

The royal family steps out in Canada on their royal tour.

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Sept. 24, 2016

Kate and Charlotte have a sweet moment after arriving in Canada!

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Sept. 24, 2016

George shows off his silly side in Canada.

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July 22, 2016

Kate and William released several new photos of George for his third birthday back in summer 2016.

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July 22, 2016

George posing on the Kensington Palace grounds.

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July 22, 2016

George with the family's dog, Lupo — how cute!

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July 22, 2016

George sitting on a handmade, wooden swing given to Kate and William.

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July 8, 2016

George stepped out with his mom, Kate, for a royal event in summer 2016.

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June 11, 2016

Kate, Charlotte, George, and William pose on the Buckingham Palace balcony.

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May 1, 2016

Charlotte poses in new photos released for her first birthday in 2016.

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May 1, 2016

Kate took these photos of Charlotte at the family's royal residence.

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May 1, 2016

Charlotte in her playroom — so adorable!

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May 1, 2016

Charlotte playing on the Kensington Palce grounds.

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April 22, 2016

George met former US President Barack Obama at Kensington Palace in spring 2016.

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April 22, 2016

The royal family meeting the Obamas.

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April 20, 2016

Queen Elizabeth poses with some of her grandchildren and great-grandchildren.

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April 20, 2016

George poses for an official portrait with dad, William, grandfather Prince Charles, and great-grandmother Queen Elizabeth.

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March 3, 2016

The royal family on a ski trip in March 2016.

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March 3, 2016

Kate and William pose with their two children on vacation.

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March 3, 2016

A sweet snapshot of Charlotte and her dad, William.

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March 3, 2016

George and Charlotte are all smiles with their famous parents.

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Dec. 18, 2015

The royal family's 2015 Christmas card photo.

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Nov. 29, 2015

Charlotte in fall 2015 at the royal family's residence.

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Nov. 29, 2015

Kate took these adorable photos of her baby daughter — how cute!

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Jan. 6, 2016

George on his first day of pre-school in 2016.

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Jan. 6, 2016

George on his first day of pre-school!

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July 5, 2015

George peeking at his younger sister at Charlotte's christening.

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July 5, 2015

Charlotte at her 2015 royal christening.

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July 5, 2015

Kate and Charlotte at the royal baby's summer 2015 christening.

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July 5, 2015

George and William at Charlotte's christening.

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July 5, 2015

The royal family pose at Charlotte's christening in July 2015.

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June 6, 2015

George and his younger sister shortly after her May 2015 birth.

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June 6, 2015

George sweetly plants a kiss on his younger sister's forehead.

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June 6, 2015

George and Charlotte in summer 2015.

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May 2, 2015

George and William outside the hospital after Charlotte's birth.

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May 2, 2015

One of the first photos of baby Charlotte!

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May 2, 2015

Kate and William pose with newborn Charlotte after her birth.

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December 13, 2014

George posed for photos at the royal family's residence in winter 2014.

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December 13, 2014

George in winter 2014.

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December 13, 2014

George posing for new photos released to the public in December 2014.

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July 21, 2014

George with his parents on the royal family's tour of Australia and New Zealand.

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July 21, 2014

Kate, George, and William visiting Australia.

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April 9, 2014

George playing during the family's royal tour of Australia and New Zealand in 2014.